Merge branch 'rubocop'

* rubocop:
  Additional fixes for rubocop 1.10.1
  Switch to rubocop 0.89.1

Switch to rubocop 0.89.1

This is the rubocop in new Debian stable

Usage command

Customer has a CustomerUsage which can fetch data to build a UsageReport
which returns a jabber:x:data form "table" as per spec for per-day in
the last month.

Minutes come from cdr table in postgresql.
Messages come from redis.